How will you ensure that my house has proper ventilation?

Ventilation is one of the most critical components to the quality of indoor air. Installing and operating a mechanical ventilation system provides the homeowner with a continuous supply of fresh air. This eliminates reliance on natural weather conditions and leaks in the structure to provide fresh air for the home.

There are three basic ways for mechanical ventilation systems to work: exhaust-only, supply-only, and balance supply and exhaust systems.

Exhaust-only systems can create a strong negative pressure on the home, introducing radon and moisture into the home, so care should be used in determining appropriate applications for these systems.

A supply-only system pushes fresh air into the home creating a positive pressure. This forces moisture out of the house and can cause condensation problems inside the wall cavities if used in cold climates with elevated relative humidity. This could be the system of choice in hot humid climates.

A balanced system is designed to maintain a neutral pressure inside the home with little pressure difference in the structure. This system will typically recover some of the energy from the exhaust stream as well, and is referred to as a heat recovery ventilation system (HRVS). HRVSs recover any heated or cooled air that is being exhausted and tempers, or cools, the incoming air for energy efficiency.

Another type of mechanical ventilation uses energy recovery. An energy recovery ventilation (ERV) system acts as the lungs for the home providing a continuous supply of fresh, filtered air, while exhausting the stale, contaminated air. In the winter months, the ventilator captures 80% of the heat energy from outgoing air and transfers it to the incoming fresh air before circulating it through the home. This reduces the cost to heat and cool fresh air coming into the home. The ERV system operates on about the same amount of energy as a 100-watt light bulb.

A low-speed continuous ventilation system, with high-speed capability, that will provide a complete air change once every three hours is ideal for indoor air quality. This change rate helps to eliminate any build-up of moisture that can cause mold, mildew and other indoor air quality problems.